It is common practice when working at home with epoxy resin materials to use a sheet of aluminum foil as a base upon which measured amounts of resin and catalyst can be drawn out next to each other and then mixed prior to use. While this is fine for home use, it is obviously inappropriate for the large amounts of material used in commercial or industrial applications. For such applications, a convenient means must be provided for handling large quantities of the materials. In prior attempts to solve this problem, devices have been provided in which deformable tubes of the two components would be placed into a cartridge similar to a caulking gun. The ram in the caulking gun would then be advanced to extrude the two materials from the nozzle of the gun. Using this technique, it was very difficult to control the proportional mixing of the two materials. The more dense and larger volume material--the resin, would often overwhelm the package containing the catalyst forcing it to expel its contents prematurely followed by the resin. In that case, there would be no mixing of the two components and the necessary hardening would not take place.
In an attempt to overcome the above-mentioned problem, devices have been built in which a separate tube of resin and a separate tube of hardener would be placed in a holder with the closed flattened ends of the two tubes fixed between two rollers which would then be advanced to extrude the material from the two tubes. While this system prevented the larger resin tube from overwhelming the catalyst and did enable the two materials to be expelled in the correct proportions, it also created a substantial problem in that the catalyst was led through a fixed tube to a nozzle, and the resin was led in a similar manner through a fixed tube to a nozzle where the two materials would come together. Because of this construction, if the bonding process was going to be stopped for any period of time--for example, a period as short as a lunch break--the nozzle had to be carefully cleaned to prevent the resin from hardening in place destroying the usefulness of the gun. The latter systems also employed a complex system of worm gears, driving gears and rollers to extrude the material from the separate tubes.